So what's the difference between Christian and Catholics? (read the entire question before answering)?

I believe the true answer is that catholics believe in transubstantiation, which I am fairly confident is the belief that the wine and eucharist (the little cracker) are actually transformed into the blood and body of christ as they are blessed and consumed, while other branches believe the wine and eucharist or host to be merely a representation of the blood and body of christ. I 'm no priest, but I am fairly sure that is the case...